<clickhouse>
   <dictionary>
       <name>dep_z</name>
       <source>
           <clickhouse>
               <host>localhost</host>
               <port>9000</port>
               <user>default</user>
               <password></password>
               <db>dict</db>
               <table>dep_y</table>
               <invalidate_query>SELECT intDiv(count(), 4) from dict.dep_y</invalidate_query>
           </clickhouse>
       </source>
       <!-- ExternalLoader::PeriodicUpdater::check_period_sec=5 anyway -->
       <lifetime>4</lifetime>
       <layout>
           <flat/>
       </layout>
       <structure>
           <id>
               <name>id</name>
           </id>
           <attribute>
               <name>b</name>
               <type>Int32</type>
               <null_value>-3</null_value>
           </attribute>
           <attribute>
               <name>a</name>
               <type>String</type>
               <null_value>ZZ</null_value>
           </attribute>
       </structure>
   </dictionary>
</clickhouse>
